Clutch mechanism



w. H.,SILVER CLUTCH MECHANISM Filed 001;. 26, 1942 April 22, 1947.

3 Sheets-Sheet 1 INVENTQR April 22, 1947. w. H. SlLVER CLUTCH MECHANISM 3 Sheets-Shec 2 Filed Oct. 26, 1942 INVENTOR H. Silver Walter A ril 22,- 1947. w. H. SILVER 2,419,467

CLUTCH MECHANEESM Filed Oct. 26, 942

3 Sheets-Sheet 3 lNVENTOR Wolier H. Sliver Patented Apr. 22, 1947 UNITED STATES PATENT OFF l C E CLUTCH MECHANISM I Walter H. silven'Moline, Ill., assign'or'tofDeere'&

, Company, Moline, 111., a

nois

corporation "of Illi- Application'flctober 26, 1942, Serial No. 463,441

..nect, thereby raising or lowering the tool or tools or other implement part. Under some conditions,-however,-if the operator did not release the manually-operated member quickly enough, the

half-revolution clutch mechanism might remain h,

engaged so that it would not stopat the end of thefirst cycle but would go into and complete the second cycle before the operator could release the manual control.

The object and general nature of the present invention is the provision of self-interrupting clutch mechanism for agricultural implements and the like in which the control isTarr-anged so .that the connectionsbetween themanual control member and the clutch mechanism are automatically disconnectedby the movement of the driven member of the clutch into or through a given position, whereby the actuation of the clutch mechanism is automatically terminated at the end of the 'first cycle, as is desired, irrespective of whether or not the operator releases the manual member at the proper instant.

One feature of my invention is the provision of a two-part clutch controlling member, in which the partsare connected by a latch that is released when the driven part of the clutch moves a predetermined amount, whereby the position-of one part is then independent of the position of the other part.

More specifically, it is a feature of-this invention to provide a clutch control'in which amanually operated member is connected through toggle-links with the clutch controlling latch "do the toggle links being constructed andarranged so that the toggle is broken or disabled by the vmovement oi-the driven member of the clutch, therebypermittingthelatch dog to return to-its normal clutch disconnecting position, even though the operator may still .hold the manually operated member in its clutch connecting position. Thus, it is impossible for the mechanism .to move through more than one cycle at .any

onetime.

These and other objects-and advantages of the present invention will be apparent .to those skilled 5-5 of'Figure 3;

in the .art after a consideration of the following :detailed description, taken in conjunction with the accompanying "drawings.

In the drawings:

Figure 1 is a plan viewof a portion of an agriculturalimplement in which the principles of the present invention havebeen' incorporated;

.Eigurezis a side view of the structure'shown in Figure 1; Figures 3 and 4 are enlarged "fragmentary views illustrating the action of the automatic latch .dog return and connection disabling meche anism;

.Figure'i5 is a view taken generally along the line Figure 6 is a sideview of a modifiedjform. of the present invention, particularly adaptedfor towed. plows and like implements;

Figure '7 is an enlarged fragmentary sectional view taken generally along the line'.|-,| ofz'Figure 6; and

Figure'8 is a view, similar to'Figure 6, taken generallyalong the lineB-S ofFigure 7.

Referringnow .to the drawings, .more particularly Figures 1 and2, the agriculturalimplement,

shown fragmentarily, in Figures 1 and 2, that has been chosen to illustrate theprinciples of the present invention, is a tractor drawn toolbar cultivator like that shown in my U. S. PatentNo.

2,385,950, issued October'Z, 1945, to which reference may-be made if necessary. Briefly, theimplement, which is indicated in its entirety by the reference numeral I, includes a generally forwardly extending hitch frame-'2, the rear'por- ,tion of which is .iormed by .a transversely disposed tool bar'3 upon which tools such asone or more lister bottoms prior patent,the implement frame 2is relatively wide so as to accommodate a considerablenumber of toolsand is provided with a'pair of vpower actuated lifting means, each including a crank axle l0 and a ground wheel l'l. Preferably, the crank axle or swinging member "ID includes a pair of bars l4 and [5 which at theiriorwardor lower ends carry an axle l6 upon which the ground wheel II is journale'd'for rotation. Associated with the ground wheel 'I l isa power lift clutch N3 of .the self-interrupting or half-revolutiontype, which incorporates a driving member (not shown) secured to or driven by the wheel II and a driven member [9 of which the axle I6 is a part. .Apair of cranks 2l' and'22 are connected to .the axle l6 and act through upwardly extendinglinks 23 (Figure2) to raise'the'fram'ei,

l are adapted to be secured, as .by clamping means'i. As best shown in'said,

the upper ends of the links being connected by arms 26 to a lifting rockshaft 21 which is normally held in adjusted position by a lever and detent mechanism 28. The rear ends of the bars [4 and 15 making up the crank axle ID are pivoted, as at 3! (Figure 2), to a pair of brackets 32 (Figure 1) secured by U-bolts 33 to the tool bar 3. The brackets 32 preferably comprise generally U-shaped strap members, and the laterally outer brackets 32 includes one section 32a that extends downwardly beyond the other section and is apertured to receive a pivot bolt 35 on which an actuating lever 36 is mounted. The rear end of a cable 31 is fixed to the upper end of the actuating lever 36 and extends forwardly and is trained through a pulley 38 carried on a bracket 39 forming a part of the laterally outer arm 25, and the cable 31 is extended forwardly, as at 31a, to the operator's station on the tractor.

The self-interrupting clutch i8 is constructed substantially like the clutch disclosed and claimed in my U. S. Patent No. 2,346,514, issued April 11, 1944, to which reference may be made if necessary. Briefly, the clutch includes aninner clutch dog (not shown) which is controlled by the movement of the clutch casing, indicated by the reference numeral 43 in Figure 2, relative to the driving parts of the clutch, and the casing is provided with a pair of generally oppositely arranged notches 4i and 42, in either of which the roller 43 on a pivoted latch dog 44 is adapted to engage;' The latch dog 44 is mounted for pivotal movement on a stud 45 that is fixedto the outer crank axle bar l (Figure 1). The latch dog 44 is best shown in Figure 5, from which it will be seen that the latch dog 44 includes a pair of strap members 41 and 43, both mounted on the stud 45 and carrying a pin upon which the roller 43 is mounted, together with a casing-engaging auxiliary ro1ler'5i' also mounted on said pin. An arm 53 is fixed, as by welding or the like, to the upper ends of the latch dog straps 41, 48, and the arm 53 extends generally rearwardly and is'apertured to receive the adjusting bo1t'54 of a biasing spring 55. The lower end of the spring 55 is secured to an anchoring bracket 55 that is welded or otherwise fixed to or connected with the crank axle bar l5. When the parts are arranged as shown in Figure 2, which is the normal operating position in which the frame is lowered and the tools 4 operating in the soil, the roller 43 is disposed in one of the notches 45 or 42, the notch 42 as shown in Figure 2, in which position the driving and driven members of the clutch l8 are held in disengaging position by means,

including a locking late 58, carried by and movable relative to the driven clutch member.

Whenever the latch dog 44 is moved in a clockwise direction (Figures 2 and 3), the roller 43 is moved out of the notch 42 and this permits the clutch connecting means within the casing 4K! to connect the driving and driven clutch members, whereupon the rotation of the ground wheel ll serves to swing both cranks 2i and 22 generally rearwardly and upwardly (Figure 2), thus raising the frame relative to the ground wheel, the crank axle l8 swinging downwardly about its pivots 3!. When the clutch parts are connected the casing 40 rotates with the axle shaft l6 and cranks 2|, 22, and during this action, the auxiliary roller 5! (Figure 5) rolls along the flange 40a of the casing 46, in which flange the notches 4| and 42 are formed. The spring 55 acting through the arm 53 exerts a continual bias against the latch dog 44 tending to cause it to enter the next notch which reaches it during the rotation of the casing 46 when the clutch parts are connected.

According to the principles of the present invention, connecting means between the actuating lever 36, which is manually controlled, and the clutch dog 44 is provided which may be disconnected in response to a given or predetermined movement of the driven clutch part, such as the casing 4. To this end, I have provided a toggle mechanism, indicated in its entirety by the reference numeral and which comprises a first toggle link 6| pivoted, as at 62, at its rear end to the actuating lever 36 at a point that is closely adjacent the axis 3i, 3! of swinging movement of the crank axle i8. It is for this reason that the bracket extension 32a, on which the actuating lever 35 is pivoted at 35, is provided. A second toggle link 64, which is preferably in the form of a U-shaped member, is pivoted at one end to a bracket welded to the link 6| adjacent its forward end, the other or forward end of the second toggle link 64 being extended, as at 66, through both of the straps 41 and 48 of the latch dog 44 (Figure 5). The longer toggle link 6| is extended, as at 69, and is provided with an abutment ii that serves as a stop engageable with the end 66 of the second toggle link 64 to define the extended or locked position of the toggle links BI, 64. The link 61 is provided with a small bracket 13 to which a spring 14 is connected, the spring being anchored to a clip 15 welded to the bar l5 of the crank axle [5, as best shown in Figure 3. The spring 14 thus biases the toggle links for movement into a locked position, which is determined and maintained by the engagement of the stop H with the second toggle link 64. The extension 69 of the first toggle link 6| is carried laterally and downwardly, as at 69a, to position the end thereof directly in the path of movement of the flange 40a of the casing 49.

The operation of the preferred form of this invention as described above is substantially as follows.

Figure 2 shows the parts when thetools are in ground engaging or operating position. Assuming that the operator desires to raise the tools 4 into an inoperative or transport position, he exerts a pull on the cable 31, 31a which swings the actuating levers 36 forwardly, mention being made above of the fact that the implement I includes lifting clutch and crank axle means at each side. As best shown in Figure 3, whenever the actuating lever 36 is swung forwardly, or clockwise as viewed in Figure 3, a thrust is transmitted through the extended or locked toggle links BI and 64, swinging the latch dog 44 about its pivot support 45 in a clockwise direction, which moves the roller 43 (Figure 1) out of the notch 42 (Figure 2). This movement permits the clutch parts to engage and connect the driven clutch member to the driving clutch member, whereupon the forward travel of the machine causes the ground wheel II to rotate and swing the cranks 2|, 22 in a clockwise direction, the casing 40 moving with the cranks. Referring now to Figure 3, and remembering that the toggle link extension end 69a is in the path of movement of the casing flange 40a, it will be seen that after the clutch has been rotated through approximately thirty degrees, one side of the notch 42 will come into contact with the end 69a of the toggle link 6|, moving it upwardly into the position shown in Figure 4, thus breaking the toggle and disabling arrears? '6 the-connection between the-actuating lever- 36 and The clutch latch dog- [t6 preferably comprises 'the lateh-dogM. soon as the pivotpoint 'bea-pairof-strap-members I-U'Land' I IJB CF'igure'l) tweemthetoggle linRs- BI -an'd 'B' I passes-above a suitably-apertured so as to be mounted for piv- -l ine--'connecting-the pivot 62 and the'pivot' fit, (ital/movement on "a pin I09 'carried-byithe vaxle the'sprin'g-55 then-'acts'to return-'the-latch 'dog housing 81. The upper endsof the latch ldog "M'to 'ap'ositio n-in whichthe auxiliary roller 5| straps-1B1 and IUB -are-connected to ether by a rides alongthe' periphery of thefiange-dfla this cross piece-II l 'whichexten'ds laterally inwardly, being the position shown in Fig-ure l. -It will be as -at I-I2, and is aperture'd at 112 to receive a observed that this-action takes placeeven though threadedadjustingspringbolt I I3. A spring I I4 "the manual-control actuating lever36 is'held in its 1-0 is-connected at its upper end'to the adjusting forward position. Thus,-even though the-oper- -bolt-11 3 andat itS lower end to a-lug I I5 Fig- -ator" fails to release thecable 31,the-latch dog ure 6) forming a part-of the axle housingsocket -M-is in-a position to-disengage ordisconnect "86. "The lowerends oi the-strapmembersfll'l "theclutehupon the completion ofthe' half-revoluand-I08 are connected together We pin .I Il8 tion-cycle, at which --time theroller 43 -eng-ages upon which -a pairot rollers HQ-and 120 :'are the notch 4|, thus terminating the clutch action mounted. The roller I-I9 is disposed in theplane anddisconnectingthe clutch. The toggle is then of the-plate or flange IllI, while theoth'er roller reset by'the perator releasing his-'holdonthe 1204s disposed'in theplane of the clutch-con- -cable-3'I, permitting the lever- 36 to swing reartrolling dog I05.

wardly until the'spring 14- swings the toggle link- An-actua-tinglever, indicated in its entiretyiby 6i downwardly until the links-6| -'and-64 occupy the reference-numeral I25, for operating theai1atch "the position showin Figure 2, which position -'dog-I'06, -is'also mounted for rockin ove ent is determined by the-engagement of the stop or "on thepin-IIIB, as best shown in Figure '7. The abutment II with the end: 65 of the link -64. It actuating lever IZ'B inCIudesastrap member I26 will be seen, particularly from Figures-3 and 4, having a slot IZ'Iiorme'd-adjacent the'upper-exthat the spring" also-serves as means for swingended end-H801 the'latc dog "Strap The ing the actuating lever 36- rearwardly. If desired, t ded port on 28 is provided :with an op n of course, a spring maybe connected directly "end slot I29, theslot "IZ'I'eXtendingashortdiswiththe lever 36 to return it to its rear position. "tance above the end-"of the'sec'tion 1-28. Arod Figures 6;? ands illust t modified form 30 I I31 is disposed in a generally'vertical position ofthepresent invention in'whichthe'cable-cond a anendl32= disposed in the slots I2Izand trolled clutch operatingmember' is mounted on I29 when the lever-I-25 isconnected to=the latch the-crank axle, as is'usuallythecase insuch im- I mi lower 'o the 'O [3| i5 D V d plements as towed plows and the like, rather than with a laterally turned p y son the'frame'asin theimplementdescribed-above. 35 posed an aperturefermed i e of Referring now more particularly toFig &3 the bell crank 136 also mounted for rocking the plow isindicated' in its entiretyby the refermovement n the p Hi9,v p e e bly betweenthe enee numera 30 d incmdes 'agenerallylongistrap members I01 and Hi8 of the latch dog.xl.n6. "tudinally extending beam 8|, the'front end of A Second arm I31 of e l crank is ape wh'ich is'provided'with suitableldraft-means (not 40 TEceiVe the lower End Of a p *shown) for connecting'the implementto a source upper end of which is Connected ya of"power and the rear end'of is'adapted or t0 the aCtuatlng lever to carry, in any suitable manneryone or more S best Wn' in Figure 8, the Sprin |33el0tS1t0 t -gz B01ted-to the beam 3| is a hold the latch rod I3! in a position connecting supporting b1'acket83 carrying suitable bearing 5 the'level with the latch dog A11 abutmeans in which the horizontal portion of a, ment extension MI is formed on thelbell crank crank'axle 85 is disposed for swinging movement. and, as best Shown in Figure 7, is disposediin Fixed to the m crank axle 5 is the path of movement of the notchedportions the socket portion 86 of an axle housing 81, th H12 and I03 of the driven clutch plate member lower. portionof which includes agenerally hori- 'zontally disposed'sleevesection in'which a crank The oPeration of this form of the invention is shaft as is disposed. A lifting arm-a9 is fixed, eubstenilelly as follows:

as bywelding, to theinner 'end'of the axle shaft when the Operator pulls on thecabie (Figand is connectedlby a lifting link 9| to adepth ure 6), the forward movement of the actuating adjusting lever 92'which is connected, asby a lever I25'acts through the latch rod I3l to swing vpivot-{bolt 93, tovthe-ibeamraL A Sector 94 the latch dog I06 in a clockwise direction (Figoperates with detent mechanism 95 carried'by the ure e shifting; the rollers l9 and away lever 92 for locking the latter in different posi -from the clutch unit m0. AS 50011 as the. latch tions. A ground wheel 99 is journaledfor rotadog is dieeneeeed Clutch dog tion on the axle 88 and is connected to drive a the latter moves into a position connecting the self-interrupting clutch unit m which, in turn, driving and driven rs of the c utchrwheredrives the axle shaft88 and the'lifting crank 89 upon forward travel of the plow and Ythe when the clutch unit connected The clutch resulting rotat1on of thewheel 99 starts theclock- I0!) is of conventional construction and'need not W159 d the 'clutch'patats f described in detaiL Briefly, suchlclutch (see Figure 8), eventually swinging the liftlng cludes a drive member to'which the wheel 99 is i 89 t appmxlmately ninety degrees fixed and a driven member'of which the plate IIll Whlch 'permlts the beam 1 Pssmiated parts is a part the plate having a pair of oppositely tolower. However, at thelbeginmng of the lower- ..armnged notches m2 um The engagement ing-movement, the driven clutch member IOI 1s and disengagement of the driving and driven rotated in a clockwise direction (Figure 6) :and clutchparts is controlled by a, clutch dog I05, as the longer portion of the notchedsection'lflii and the position of theclutch dog on'the driven of:the member IUI comes into engagementzwith m 0 t n i a latch dog the-abutment portion I II of the bell crank J36, H16. and associated mechanism, with which the as shown: in Figure-8, the bell tcrankl'member :is

pres'ent'invention-is more-particularly concerned. -swung a counterclockwise direction, I QWhi-Ch forces the latch rod I3I into the upper end of the slot I21 and releasing the latch dog I06. As soon as the upper end I32 of the latch rod I3I is disengaged from the notch I29, the spring II4 immediately rocks the latch dog I06 in a counterclockwise direction and disposes the roller I20 in a position against the edge of the flange IUI and ready. to reengage the notch I62, entirely irrespective of whether or not the operator releases the cable I50 by the time the clutch mechanism moves through a half revolution. Thus, the clutch movement is limited to a half revolution, entirely irrespective of whether or not the operator releases the cable or maintains his hold on the cable. However, as soon as the cable I50 is released, the actuating lever I25 is returned to its rear, position by any suitable means, such as a spring II, the upper end of the latch dog extension I28being inclined so as to lift the latch rod I3I to the upper end of the slot I21 whereupon the spring I5I then reengages the latch rod I3I with the notch I29 in the extension I28 of the latch dog I06, thereby restoring the connection between the actuating lever I25 and the clutch controlling latch dog I06.

While I have shown and described above the preferred structure of the present invention, it is to be understood that my invention is not to be limited to the particular details shown and described above, but that, in fact, widely different means may be employed in the practice of the broader aspects of my invention.

What I claim, therefore, and desire to secure by Letters Patent is:

1. In an agricultural implement, having a part to be moved from one position to another, selfinterrupting clutch means for shifting said part and including a member movable into a position for causing said clutch to shift said part and a projection movable with the clutch during operation thereof, releasable control means connected with said member and including an abutment extending normally into the path of movement of said projection and movable generally in the same direction when said projection engages said abutment, and means responsive to movement ofthe abutment in said one direction for releasing said control means.

2. In an agricultural implement, a self-interrupting clutch, a movable control part for controlling said clutch and biased for movement into a position disconnecting said clutch, means including disconnectible parts for moving said part against said bias into a position connecting said clutch, one of said parts including pivoted arm means having an end extending toward said clutch, and means carried by said clutch engageable with said arm end for shifting the latter and disconnecting said disconnectible parts so as to permit said control part to be moved by said bias into a position disconnecting said clutch.

3. Tripping mechanism for a self-interrupting clutch for agricultural implements and the like, said clutch having a controlling part and including an optionally driven member, said tripping mechanism comprising a pair of toggle links, means separate from said toggle links urging said controlling part to an engaging position, means acting through said toggle links when in extended relation for actuating said controlling part, and means responsive to a predetermined movement of said driven member and acting against said bias from breaking said toggle links and permitting the movement of said controlling part to its engaging position independently of the position of said toggle link actuating means.

4. A self-interrupting clutch comprising clutch mechanism including driving and driven parts, a member for controlling said mechanism, means biasing said member for movement into a position to disconnect said driving and driven parts, means including a pair of toggle links, means acting to transmit force through said toggle links, when in extended position, for moving said member against said biasing means to connect said driving and driven parts, and means responsive to a predetermined movement of said driven member for disabling said toggle links, thereby permitting said controlling member to return to said position.

5. An agricultural implement comprising a swingable crank axle, a wheel thereon, a wheel driven self-interrupting clutch unit including driving and driven members and mechanism releasably connecting said members, a part pivoted on said crank axle normally biased for movement into a position disconnecting said driving and driven members, means including a pair of toggle links connected with said pivoted part, means acting to transmit force through said toggle links, when in extended position, for moving said pivoted part into a position providing for the connection of said driving and driven members, and means responsive to the movement of said driven member for breaking said toggle and permit ng said pivoted partto move into a position disconnecting said driving and driven members.

6. In an agricultural implement, a support, a crank axle movablymounted on said support for swinging movement about an axis, a pivoted clutch controlling latch dog mounted on said swingable crank axle, an actuating lever pivoted to said support for movement about an axis, a pair of pivotally interconnected toggle links pivotally connected, respectively, with said actuating member and said latch dog, yielding means holding said toggle links in extended operative position, whereby movement of said actuating lever acts through said toggle links to shift said latch dog, and means for disabling the connection between said actuating member and said latch dog by moving said toggle links into an inoperative position.

7. The invention set forth in claim 6, further characterized by biasing means acting against said latch dog for swinging the same into one position, said actuating lever acting through said toggle links for shifting the pivoted latch dog into another position against the action of said biasing means, the latter serving to return said latch dog to said one position when said toggle links aremoved into their inoperative position.

8. In an agricultural implement, self-interrupting clutch mechanism including a movable latch dog and driving and driven members, means for operating said latch dog for driving an actuating member, a pair'of toggle links connected between said actuating member and said latch dog and normally heldin extended operating position, whereby movement of said actuating membenacts through said toggle links in their extended operating position for shifting said latch dog, and means responsive to the movement of one of said members for moving said toggle links into an inoperative position.

- 9. In an agricultural machine, a self-interrupting clutch including driving" and driven parts, a pivoted latch dog therefor. biased'for movement into a clutch disconnecting position, means for moving said latch dog out of Said position including a pair of toggle links, one of said links including a section extending over into the path of movement of a part on one of said driving and driven parts, and an actuating member acting through said toggle links for moving said latch dog, movement of said one member acting through said extension for breaking the toggle and permitting said latch dog to move into its clutch disconnecting position independently of the position of said actuating member.

10. An agricultural implement comprising a swingable crank axle, a wheel thereon, a wheel driven self-interrupting clutch unit including driving and driven members and mechanism releasably connecting said members, a part pivoted on said crank axle normally biased for movement into a position disconnecting said driving and driven members, a lever for operating said part mounted for movement about the aXis of movement of said part, a shiftable latch carried by said lever and adapted to releasably engage said part, spring means acting against said latch for moving the latter into engaging relation with said part, and a second lever also mounted for movement about the axis of pivotal movement of said part and connected with said latch, said second lever including a portion disposed in the path of movement of said driven clutch member whereby movement of the latter through a given extent shifts said latch into a, position disconnecting said first mentioned lever from said pivoted part.

11. In an agricultural implement, a support, a

crank axle movably connected with said support and carrying at its swinging end a controllable clutch, a latch dog movably mounted on said swingable crank axle for controlling said clutch, an actuating lever pivotally mounted on said support for movement about an axis closely adjacent the axis of said swingable crank axle, and means connecting said actuating lever with said pivoted latch dog, said last mentioned means comprising a toggle linkage connected at one end with the actuating lever and at the other end with said pivoted latch dog.

12. In an agricultural implement having a movable part, means for moving said part, releasable means including a control member and adapted to normally hold said movable part against movement, the combination therewith of end with said pivoted latch means for operating said control member comprising an operating member, disconnectible means connected between said operating member and said control member and including a first toggle link connected at one end toone of said members, a second toggle link pivotally connected to the other end of said first toggle link and including a section extending beyond said first toggle link, stop means carried on said toggle link extension and engageable with said first toggle link to limit the position of one link relative to the other, and means movable with said movable part in such a path of movement as to be engageable with said toggle link extension for moving said links into a disconnected position after the occurrence of a given movement of said movable part.

13. In an agricultural implement, a support, a crank axle movably connected with said support and carrying at its swinging end a controllable clutch, a latch dog movably mounted on said swingable crank axle for controlling said clutch, an actuating lever movably mounted on said support adjacent said swingable crank axle, and means connecting said actuating lever with said pivoted latch clog, said last mentioned means comprising a toggle linkage connected at one end with the actuating lever and at the other dog.

WALTER H. SILVER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 519,173 Campbell May 1, 1894 2,178,205 Johnson Oct. 31, 1939 2,204,421 Loshbough June 11, 1940 2,259,297 Cramer Oct. 14, 1941 1,719,705 Loshbough Apr. 30, 1929 1,853,766 Hahnemann Apr. 12, 1932 2,256,039 Axtell Sept. 16, 1941 1,669,037 Boda May 8, 1928 1,140,428 Winter May 25, 1915 1,682,373 Davis Aug. 28, 1928 FOREIGN PATENTS Number Country Date 778,652 French Jan. 2, 1935 

